title check fluctuating heavy-element abundances 
c commands controlling continuum =========
blackbody 5
ionization -2
c 
c commands for density & abundances =========
hden 3
c this varies the abundnaces between default and 1e-4 times default,
c over a 1e10 cm period - we will compute half a cycle
fluctuatsion abundances 10.3 0 -4
c 
c commands controlling geometry  =========
c stop at half a cycle so pick off lowest abundances
stop thickness 10
c 
c other commands for details     =========
c speed things up a bit
init "c84.ini"
c
c commands controlling output    =========
print column density
save performance "func_abund_fluc.per"
save monitors "func_abund_fluc.asr"
save overview "func_abund_fluc.ovr"
save abundances "func_abund_fluc.abn"
c
c commands giving asserts
monitor hydrogen 2 temperature 4.228
monitor hydrogen 1 ionization -3.148
c
c func_abund_fluc.in
c class function 
c ========================================
c 

This checks that the variable abundances option works